This invention relates to a ski system incorporating linkage to cause skis to operate in coordinated fashion and, in particular, to a system having a linkage for interconnecting three skis.
Snow conditions can vary widely from place to place and even from day to day. It is more difficult and less enjoyable to ski when conditions are marginal, e.g. excessively deep "powder" or an icy crust on the snow. A typical ski is narrow and has a relatively low surface area for its length. Consequently, the ski applies a pressure greater than powdery snow can support and the ski sinks into the powder, slowing the skier. A problem with ice is that the edges of the skis provide some control on ice but the forces on the skis can exceed the breakaway force of an edge. If so, a skier can slide sideways, or worse.
This invention relates to high performance skis particularly suited to marginal conditions. By high performance is meant skis which permit a skier to move as quickly as possible, either in terms of speed or in terms of changing direction. Adding a third ski and coupling it to the other skis will increase the surface area in contact with the snow and add an edge for control on ice. However, a problem is thus created when adding the third ski to the others; that is, the ski must be added in such a way that performance in good snow conditions is not compromised.
The known prior art relating to interconnected or coupled skis is generally concerned with sleds. As used herein, skiing refers to a system wherein the skier's feet are mounted directly (by way of boots and bindings) to the skis and the skier's feet control the skis. Sleds are typically provided with two or more skis and utilize a steering/tilting mechanism for controlling the skis.
In most sleds, a central or main ski is balanced by two outrigger skis, one on each side of the main ski. In some cases, the skis are in a side-by-side or overlapping relation and in other cases the middle ski is forward of the outrigger skis and there is no overlap between the middle ski and the outrigger skis (the heel of the middle ski is ahead of the tips of the outrigger skis). The outrigger skis are either rigidly attached to the central ski, e.g. as disclosed in U.S. Pat. No. 3,666,281 (Billings), or are connected to the central ski by a complicated mechanism for tilting at least the outrigger skis as the rider leans from side to side, e.g. as disclosed in U.S. Pat. Nos. 3,540,750 (Berger) or 3,841,649 (McMullen).
These sleds are ridden, typically in a seated position, and do not give the same sensation, or permit the same freedom of movement, as skiing. Further, the tilting/steering mechanisms on the sleds are complicated and relatively heavy, i.e. weighing more than two or three skis.
A skier traversing a slope has one ski slightly higher than the other ski, enabling the skier to remain vertical and causing the trailing (uphill) edges of the skis to dig into the snow for directional control. Sleds of the prior art emulate this condition either by rotating each ski about the longitudinal axis of the ski or by lifting one ski relative to the other.
A ski is typically rotated by means of a parallelogram mechanism, e.g. as disclosed in the Berger patent. A ski is lifted by means of a complicated mechanism, such as disclosed in the McMullen patent, which converts rotary motion to linear motion and then back to rotary motion. Either technique utilizes a mechanism which is too large, too heavy, and too complicated for skiing equipment. Of the two techniques, lifting one ski relative to the other is preferred since such permits a rider to remain vertical while traversing a slope or leaning into a turn.
A problem with either lifting or rotating a ski is that one assumes that the snow is fairly smooth. "Rough" as applied to terrain can have different meanings, depending upon the scale one uses to measure roughness. For skiing, one wants roughness on a large scale, i.e. hills or mountains. Some skiers prefer the challenge of moguls, small mounds having diameters of a couple of ski lengths or more. As used herein, rough means having bumps of a diameter less than one ski length and, particularly, of a diameter approximately equal to the distance separating the outer skis of a triple ski.
On rough terrain, sleds of the prior art can quickly transfer the combined weights of the rider and sled to just one or two skis. At best, a rough terrain can cause a bumpy ride; at worst, the rider can lose control or spill. Particularly in rough terrain, simply rotating or lifting a ski does not provide sufficient control over the position of the skis. It is desirable that the linkage between the skis have some resiliency to accommodate rough terrain. It is also desirable that triple skis respond to canting of one ski by having the middle ski assume an intermediate canted position between the canted ski and the third ski. These capabilities would improve the performance of triple skis in all terrains and snow conditions but are not obtainable from tilting/steering mechanisms of the prior art.
When used in conjunction with the skis alone, "vertical" and its cognates refer to the direction perpendicular to the plane of the skis. Canting means rotating a ski in a vertical plane; e.g. lifting just the tip of one ski.
A snowboard is a single board to which both of a skier's feet are mounted in a fore and aft configuration. Edge control is obtained by leaning from side to side and a snowboard is more difficult to learn to control than a pair of skis. A problem with a snowboard is that there is only a single edge for directional control and control is best obtained in powder. Since a snowboard is often used in marginal snow conditions, it is desired to improve the directional stability of a snowboard while retaining the other characteristics of a snowboard.
In view of the foregoing, it is therefore an object of the invention to provide linked triple skis for skiing.
A further object of the invention is to provide a mechanically simple linkage for interconnecting skis into a set of three skis for skiing in deep powder.
Another object of the invention is to provide high performance Alpine skis having three edges for better performance in all snow conditions, particularly icy conditions.
A further object of the invention is to provide a linkage using only rotary motion for controlling three interconnected skis.
Another object of the invention is to provide a linkage using only rotary motion for lifting one ski relative to another in a set of three skis.
A further object of the invention is to provide a linkage for interconnecting three skis and controlling lift and cant of the skis.
Another object of the invention is to provide a linkage for interconnecting three skis for skiing in rough terrain.
A further object of the invention is to provide a resilient linkage for interconnecting three skis.
Another object of the invention is to provide a linkage for interconnecting three skis in which canting one outer ski causes the middle ski to cant an intermediate amount.
A further object of the invention is to provide linked triple skis for sledding wherein the linkage is more compact, lighter, and enables more aggressive manoeuvres than sleds of the prior art.
Another object of the invention is to improve the directional stability of a snowboard.